Abstract: In order to improve the optical absorption of active layer in polymer solar cells，a PSC ( Polymer Solar
Cell) with multiple optical spacers is proposed． By adjusting the refractive index distribution of multiple optical
spacers to change the distribution of incident light in the active layer，enhance the absorption of the active layer
and improve the performance of the device． Further，we use the transfer matrix method to calculate the device and
explore the influence of a PSC with multiple optical spacers consisting of undoped ZnO film and CZO ( Cs doped
Zinc Oxide) films with different doping concentration of 0． 002 5 mol /L，0． 005 mol /L and 0． 01 mol /L to the
distribution of light field and short circuit current． The simulation results show that the multiple optical spacers
provide a cascade of refractive index between the ITO ( Indium Tin Oxide) substrate and the active layer when the
CZO films with a decreasing doping concentration is deposited on ITO successively，resulting in an increase of light
absorption in active layer and Jsc significantly．

Key words: polymer solar cells, optical spacers, cs doped zinc oxide, short circuit current density, transfer matrix method